1. Field of the Invention
The present invention relates to the field of hypermedia authoring and publishing systems.
2. Background Art
Hypertext and hypermedia refer to electronic documents or works for display on electronic media such as computer display screen. Hypermedia works do not have the serial structure of printed documents in which information is presented to a reader in a fixed order. Instead, information is presented to a reader in an order interactively determined by the reader.
In a hypermedia work, information is organized into individual portions called "lexia". Lexia can be viewed as containers of data. Data contained in lexia may include text, graphics, motion video and sound data. A lexia of a hypermedia work may contain one or more embedded links to other lexia. An example of a link is a highlighted word of text. Selecting the highlighted word, for example using a mouse, initiates display of the lexia to which the highlighted word is linked. This lexia may contain additional links, both back to the previous lexia and/or to other lexia or documents.
One common use of hypermedia is in computer software help files. FIG. 1 is an illustration of an example lexia from a help file such as that used in the Microsoft Windows (.TM.) operating system. As shown in FIG. 1, lexia 100 includes a title bar 110, a text window 115, and a button bar 140. Title bar 110 contains the title of the lexia. For lexia 100, the title is "How to Use Help." Text window 115 contains the data for lexia 100, which in this case is text data describing the basic operations of Windows Help. Text window 115 also contains a number of link activation areas that provide links to other lexia. These link activation areas, designated items 125, 130 and 135 in FIG. 1, are indicated in text window 115 by bold facing and underlining of the words that constitute the links. Link activation area 125 consists of the word "links". Link activation area 130 consists of the word "maximize". Link activation area 135 consists of the word "minimize." Link activation areas 125, 130 and 135 link particular locations of lexia 100 to other lexia.
Button bar 140 contains a number of additional link activation areas in the form of buttons 120a-120b. Button 120a, labeled "Contents", provides a link to a table of contents lexia. Button 120b, labeled "Back", provides a link to the previously displayed lexia. Because the previously displayed lexia changes according to the path used to get to lexia 100, the lexia linked to by button 120a changes over time. The link provided by button 120a is therefore a dynamic link that links to different lexia at different times. Buttons 120a and 120b link lexia 100 as a whole to other lexia.
FIG. 2 shows the lexia that is opened by activating link activation area 125 (i.e. the word "links") of lexia 100. As shown in FIG. 2, lexia 200 contains a glossary entry for the term "Links". Like lexia 100 of FIG. 1, lexia 200 includes a data window 210, a title bar 215, and link activation buttons 220a and 220b. Lexia 200 also contains link activation areas 225 and 230 comprising the words "Help topics" and "pointer", respectively.
The complex, dynamic inter-linked nature of a hypermedia work makes it difficult for both authors and readers to form an accurate and meaningful picture of the hypermedia work as a whole. Prior art hypermedia authoring and publishing (or reading) systems have attempted to provide graphical representations of hypermedia works by focusing on ways to show links between lexia.
One prior art graphical depiction of a hypermedia work is illustrated in FIG. 3. As shown in FIG. 3, this prior art system depicts each lexia as the target of incoming links and the source of outgoing links. In the example of FIG. 3, the hypermedia work consists of ten lexia, represented by boxes labeled "Lexia 1" through "Lexia 10". The hypermedia work is depicted by three repeated columns of the ten lexia. In the first column, Lexia 1-10 are identified by numbers 301-310, in the second column by numbers 311-320, and in the third column by numbers 321-330. A link from one lexia to another is shown as an arrow from the source lexia to the target lexia. The second column shows all incoming and outgoing links for each lexia. For example, Lexia 2 has incoming links from Lexias 1, 3, and 6. Accordingly, each of Lexias 1, 3 and 6 contain a link to Lexia 2. Lexia 2 is shown as having outgoing links to Lexias 1, 5 and 9. Accordingly, Lexia 2 contains links to Lexias 1, 5 and 9. FIG. 5 is an alternative view of the prior art representation of FIG. 3 showing only the incoming and outgoing links for Lexia 2.
The hypermedia work illustrated in FIG. 3 consists of only ten lexia. Even with this small number of lexia, FIG. 3 is confusing and complex. As a result, it does not provide a meaningful overview of the structure and content of the underlying hypermedia work. For a typical work containing several times the number of lexia shown in FIG. 3, the graphical representation of FIG. 3 is even less satisfactory.
Another prior art method for graphically representing a hypermedia work is shown in FIG. 4. FIG. 4 shows the same hypermedia work shown in FIG. 3. In the representation shown in FIG. 4, Lexia 1-10 are located at movable locations in window 400. Links between lexia are shown as arrows from the source lexia to the target lexia. The position of each lexia can be changed by the user, for example by dragging with a mouse. As a lexia moves, the arrows indicating links remain attached. As is evident from FIG. 4, this representation of a hypermedia work also fails to provide an easily understandable overview of the hypermedia work as a whole.
Authoring a hypermedia work involves creating each lexia to be included in the work and connecting the lexia with appropriate links. A variety of methods for creating and linking lexia are provided in the prior art.
U.S. Pat. No. 4,982,244 discloses a hypertext creation system in which lexia are displayed in the form of cards containing text. A first, blank card is created by activating the appropriate menu command. The blank card is supplied with an "autolink" button. Selecting the autolink button creates a second card automatically linked to the first, and also creates a link activation button on the first card. By choosing an appropriate menu command, the second card may also be provided with an autolink button allowing the creation of further links.
Another prior art hypertext creation system is the "Storyspace" software program from Eastgate Systems, Inc. In Storyspace, lexia called "writing spaces" are displayed as boxes on a computer display screen. A link from one writing space to another is created by selecting the source writing space, selecting an appropriate menu command, and selecting the target writing space. The link can be changed to a link from or to a particular location in a lexia by selecting either the source or target writing space, choosing an edit link menu command, and identifying particular text in the writing space as the beginning or end of the link, as appropriate.
Prior art hypermedia authoring and publishing systems, though providing basic mechanisms for creating and displaying links between lexia, fail to provide an easy to use authoring and reading environment that allows authors to easily create and organize and readers to easily navigate and comprehend a hypermedia work.